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From: Alistair Popple <apopple@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: <linux-mm@kvack.org>, <nouveau@lists.freedesktop.org>,
	<bskeggs@redhat.com>, <akpm@linux-foundation.org>,
	<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<kvm-ppc@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
	<jhubbard@nvidia.com>, <rcampbell@nvidia.com>,
	<jglisse@redhat.com>, <hch@infradead.org>, <daniel@ffwll.ch>,
	<willy@infradead.org>, "Christoph Hellwig" <hch@lst.de>
Subject: Re: [PATCH v7 5/8] mm: Device exclusive memory access
Date: Thu, 1 Apr 2021 00:27:52 +1100	[thread overview]
Message-ID: <2124945.3NMGunUBXV@nvdebian> (raw)
In-Reply-To: <20210331131854.GI1463678@nvidia.com>

On Thursday, 1 April 2021 12:18:54 AM AEDT Jason Gunthorpe wrote:
> On Wed, Mar 31, 2021 at 11:59:28PM +1100, Alistair Popple wrote:
> 
> > I guess that makes sense as the split could go either way at the
> > moment but I should add a check to make sure this isn't used with
> > pinned pages anyway.
> 
> Is it possible to have a pinned page under one of these things? If I
> pin it before you migrate it then it remains pinned but hidden under
> the swap entry?

At the moment yes. But I had planned (and this reminded me) to add a check to 
prevent marking pinned pages for exclusive access. This check was in the 
original migration based implementation as I don't think it makes much sense 
to allow exclusive access to pinned pages given it indicates another device is 
possibly using it. 

> So the special logic is needed and the pinned page has to be copied
> and written as a normal pte, not dropped as a migration entry

Yep, if we end up allowing pinned pages to exist under these then that makes 
sense. Thanks for the clarification.

 - Alistair

> Jason
> 




WARNING: multiple messages have this Message-ID (diff)
From: Alistair Popple <apopple@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: rcampbell@nvidia.com, willy@infradead.org,
	linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	kvm-ppc@vger.kernel.org, hch@infradead.org, linux-mm@kvack.org,
	bskeggs@redhat.com, daniel@ffwll.ch, akpm@linux-foundation.org,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [Nouveau] [PATCH v7 5/8] mm: Device exclusive memory access
Date: Thu, 1 Apr 2021 00:27:52 +1100	[thread overview]
Message-ID: <2124945.3NMGunUBXV@nvdebian> (raw)
In-Reply-To: <20210331131854.GI1463678@nvidia.com>

On Thursday, 1 April 2021 12:18:54 AM AEDT Jason Gunthorpe wrote:
> On Wed, Mar 31, 2021 at 11:59:28PM +1100, Alistair Popple wrote:
> 
> > I guess that makes sense as the split could go either way at the
> > moment but I should add a check to make sure this isn't used with
> > pinned pages anyway.
> 
> Is it possible to have a pinned page under one of these things? If I
> pin it before you migrate it then it remains pinned but hidden under
> the swap entry?

At the moment yes. But I had planned (and this reminded me) to add a check to 
prevent marking pinned pages for exclusive access. This check was in the 
original migration based implementation as I don't think it makes much sense 
to allow exclusive access to pinned pages given it indicates another device is 
possibly using it. 

> So the special logic is needed and the pinned page has to be copied
> and written as a normal pte, not dropped as a migration entry

Yep, if we end up allowing pinned pages to exist under these then that makes 
sense. Thanks for the clarification.

 - Alistair

> Jason
> 



_______________________________________________
Nouveau mailing list
Nouveau@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/nouveau

WARNING: multiple messages have this Message-ID (diff)
From: Alistair Popple <apopple@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: rcampbell@nvidia.com, willy@infradead.org,
	linux-doc@vger.kernel.org, nouveau@lists.freedesktop.org,
	dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	kvm-ppc@vger.kernel.org, hch@infradead.org, linux-mm@kvack.org,
	jglisse@redhat.com, bskeggs@redhat.com, jhubbard@nvidia.com,
	akpm@linux-foundation.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v7 5/8] mm: Device exclusive memory access
Date: Thu, 1 Apr 2021 00:27:52 +1100	[thread overview]
Message-ID: <2124945.3NMGunUBXV@nvdebian> (raw)
In-Reply-To: <20210331131854.GI1463678@nvidia.com>

On Thursday, 1 April 2021 12:18:54 AM AEDT Jason Gunthorpe wrote:
> On Wed, Mar 31, 2021 at 11:59:28PM +1100, Alistair Popple wrote:
> 
> > I guess that makes sense as the split could go either way at the
> > moment but I should add a check to make sure this isn't used with
> > pinned pages anyway.
> 
> Is it possible to have a pinned page under one of these things? If I
> pin it before you migrate it then it remains pinned but hidden under
> the swap entry?

At the moment yes. But I had planned (and this reminded me) to add a check to 
prevent marking pinned pages for exclusive access. This check was in the 
original migration based implementation as I don't think it makes much sense 
to allow exclusive access to pinned pages given it indicates another device is 
possibly using it. 

> So the special logic is needed and the pinned page has to be copied
> and written as a normal pte, not dropped as a migration entry

Yep, if we end up allowing pinned pages to exist under these then that makes 
sense. Thanks for the clarification.

 - Alistair

> Jason
> 



_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Alistair Popple <apopple@nvidia.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: linux-mm@kvack.org, nouveau@lists.freedesktop.org,
	bskeggs@redhat.com, akpm@linux-foundation.org,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
	kvm-ppc@vger.kernel.org, dri-devel@lists.freedesktop.org,
	jhubbard@nvidia.com, rcampbell@nvidia.com, jglisse@redhat.com,
	hch@infradead.org, daniel@ffwll.ch, willy@infradead.org,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v7 5/8] mm: Device exclusive memory access
Date: Wed, 31 Mar 2021 13:27:52 +0000	[thread overview]
Message-ID: <2124945.3NMGunUBXV@nvdebian> (raw)
In-Reply-To: <20210331131854.GI1463678@nvidia.com>

On Thursday, 1 April 2021 12:18:54 AM AEDT Jason Gunthorpe wrote:
> On Wed, Mar 31, 2021 at 11:59:28PM +1100, Alistair Popple wrote:
> 
> > I guess that makes sense as the split could go either way at the
> > moment but I should add a check to make sure this isn't used with
> > pinned pages anyway.
> 
> Is it possible to have a pinned page under one of these things? If I
> pin it before you migrate it then it remains pinned but hidden under
> the swap entry?

At the moment yes. But I had planned (and this reminded me) to add a check to 
prevent marking pinned pages for exclusive access. This check was in the 
original migration based implementation as I don't think it makes much sense 
to allow exclusive access to pinned pages given it indicates another device is 
possibly using it. 

> So the special logic is needed and the pinned page has to be copied
> and written as a normal pte, not dropped as a migration entry

Yep, if we end up allowing pinned pages to exist under these then that makes 
sense. Thanks for the clarification.

 - Alistair

> Jason
> 



  reply	other threads:[~2021-03-31 13:46 UTC|newest]

Thread overview: 124+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26  0:07 [PATCH v7 0/8] Add support for SVM atomics in Nouveau Alistair Popple
2021-03-26  0:07 ` Alistair Popple
2021-03-26  0:07 ` Alistair Popple
2021-03-26  0:07 ` [Nouveau] " Alistair Popple
2021-03-26  0:07 ` [PATCH v7 1/8] mm: Remove special swap entry functions Alistair Popple
2021-03-26  0:07   ` Alistair Popple
2021-03-26  0:07   ` Alistair Popple
2021-03-26  0:07   ` [Nouveau] " Alistair Popple
2021-03-30 18:38   ` Jason Gunthorpe
2021-03-30 18:38     ` Jason Gunthorpe
2021-03-30 18:38     ` Jason Gunthorpe
2021-03-30 18:38     ` [Nouveau] " Jason Gunthorpe
2021-03-26  0:07 ` [PATCH v7 2/8] mm/swapops: Rework swap entry manipulation code Alistair Popple
2021-03-26  0:07   ` Alistair Popple
2021-03-26  0:07   ` Alistair Popple
2021-03-26  0:07   ` [Nouveau] " Alistair Popple
2021-03-26  0:08 ` [PATCH v7 3/8] mm/rmap: Split try_to_munlock from try_to_unmap Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple
2021-03-30 18:49   ` Jason Gunthorpe
2021-03-30 18:49     ` Jason Gunthorpe
2021-03-30 18:49     ` Jason Gunthorpe
2021-03-30 18:49     ` [Nouveau] " Jason Gunthorpe
2021-03-30 22:09     ` Alistair Popple
2021-03-30 22:09       ` Alistair Popple
2021-03-30 22:09       ` Alistair Popple
2021-03-30 22:09       ` [Nouveau] " Alistair Popple
2021-03-30 22:16       ` Alistair Popple
2021-03-30 22:16         ` Alistair Popple
2021-03-30 22:16         ` Alistair Popple
2021-03-30 22:16         ` [Nouveau] " Alistair Popple
2021-03-30 22:24       ` Jason Gunthorpe
2021-03-30 22:24         ` Jason Gunthorpe
2021-03-30 22:24         ` Jason Gunthorpe
2021-03-30 22:24         ` [Nouveau] " Jason Gunthorpe
2021-03-30 22:43         ` John Hubbard
2021-03-30 22:43           ` John Hubbard
2021-03-30 22:43           ` John Hubbard
2021-03-30 22:43           ` [Nouveau] " John Hubbard
2021-03-30 22:56           ` Alistair Popple
2021-03-30 22:56             ` Alistair Popple
2021-03-30 22:56             ` Alistair Popple
2021-03-30 22:56             ` [Nouveau] " Alistair Popple
2021-03-31  3:56             ` John Hubbard
2021-03-31  3:56               ` John Hubbard
2021-03-31  3:56               ` John Hubbard
2021-03-31  3:56               ` [Nouveau] " John Hubbard
2021-03-31  4:09               ` John Hubbard
2021-03-31  4:09                 ` John Hubbard
2021-03-31  4:09                 ` John Hubbard
2021-03-31  4:09                 ` [Nouveau] " John Hubbard
2021-03-31  4:15               ` Alistair Popple
2021-03-31  4:15                 ` Alistair Popple
2021-03-31  4:15                 ` Alistair Popple
2021-03-31  4:15                 ` [Nouveau] " Alistair Popple
2021-03-31 11:57                 ` Jason Gunthorpe
2021-03-31 11:57                   ` Jason Gunthorpe
2021-03-31 11:57                   ` Jason Gunthorpe
2021-03-31 11:57                   ` [Nouveau] " Jason Gunthorpe
2021-04-01  4:36                   ` Alistair Popple
2021-04-01  4:36                     ` Alistair Popple
2021-04-01  4:36                     ` Alistair Popple
2021-04-01  4:36                     ` [Nouveau] " Alistair Popple
2021-04-01 19:21                     ` Shakeel Butt
2021-04-01 19:21                       ` Shakeel Butt
2021-04-01 19:21                       ` Shakeel Butt
2021-04-01 19:21                       ` [Nouveau] " Shakeel Butt
2021-03-26  0:08 ` [PATCH v7 4/8] mm/rmap: Split migration into its own function Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple
2021-03-26  0:08 ` [PATCH v7 5/8] mm: Device exclusive memory access Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple
2021-03-30 19:32   ` Jason Gunthorpe
2021-03-30 19:32     ` Jason Gunthorpe
2021-03-30 19:32     ` Jason Gunthorpe
2021-03-30 19:32     ` [Nouveau] " Jason Gunthorpe
2021-03-31 12:59     ` Alistair Popple
2021-03-31 12:59       ` Alistair Popple
2021-03-31 12:59       ` Alistair Popple
2021-03-31 12:59       ` [Nouveau] " Alistair Popple
2021-03-31 13:18       ` Jason Gunthorpe
2021-03-31 13:18         ` Jason Gunthorpe
2021-03-31 13:18         ` Jason Gunthorpe
2021-03-31 13:18         ` [Nouveau] " Jason Gunthorpe
2021-03-31 13:27         ` Alistair Popple [this message]
2021-03-31 13:27           ` Alistair Popple
2021-03-31 13:27           ` Alistair Popple
2021-03-31 13:27           ` [Nouveau] " Alistair Popple
2021-03-31 13:46           ` Jason Gunthorpe
2021-03-31 13:46             ` Jason Gunthorpe
2021-03-31 13:46             ` Jason Gunthorpe
2021-03-31 13:46             ` [Nouveau] " Jason Gunthorpe
2021-04-01  0:45             ` Alistair Popple
2021-04-01  0:45               ` Alistair Popple
2021-04-01  0:45               ` Alistair Popple
2021-04-01  0:45               ` [Nouveau] " Alistair Popple
2021-04-01  0:48               ` Jason Gunthorpe
2021-04-01  0:48                 ` Jason Gunthorpe
2021-04-01  0:48                 ` Jason Gunthorpe
2021-04-01  0:48                 ` [Nouveau] " Jason Gunthorpe
2021-04-01  2:20                 ` Alistair Popple
2021-04-01  2:20                   ` Alistair Popple
2021-04-01  2:20                   ` Alistair Popple
2021-04-01  2:20                   ` [Nouveau] " Alistair Popple
2021-04-01 11:55                   ` Jason Gunthorpe
2021-04-01 11:55                     ` Jason Gunthorpe
2021-04-01 11:55                     ` Jason Gunthorpe
2021-04-01 11:55                     ` [Nouveau] " Jason Gunthorpe
2021-03-26  0:08 ` [PATCH v7 6/8] mm: Selftests for exclusive device memory Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple
2021-03-26  0:08 ` [PATCH v7 7/8] nouveau/svm: Refactor nouveau_range_fault Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple
2021-03-26  0:08 ` [PATCH v7 8/8] nouveau/svm: Implement atomic SVM access Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` Alistair Popple
2021-03-26  0:08   ` [Nouveau] " Alistair Popple

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